ABSTRACT The total alkaloid, tannins contents and antiulcer activity of the extracts from four selected medicinal plants were investigated. The total alkaloids content (TAC) was evaluated according to the chloride colometric method in which atropine was used as standard. While the total tannins content (TTC) was also determined using Folin Ciocalteau assay in which gallic acid was used as a standard. The antiulcer activity of the extracts was investigated using the ethanol induced model in wistar albino rats. Parameters such as gastric volume, pH and ulcer index were used as indicators for the antiulcerogenic activity of the extracts. The animals were orally treated with distilled water (Normal control group), ranitidine 5 mg/kg (standard control group), 0.5 mg/kg of ethanol (Negative control group) and 100,200 and 400 mg/kg of the extracts, 1 h before oral administration of absolute ethanol to induce gastric mucosal injury. The result showed that E. deightonii extract has the richest source of alkaloids and tannins (0.850 ± 0.001 mg AE/g and 0.133 ± 0.001 mg GAE/g respectively, while A. hispidum and P. staudtii has the least TAC and TTC (0.800 ± 0.001 mg AE/g) and (0.124 ± 0.001 mg GAE/g) respectively. The extract was considered safe with the LD50 greater than 5000 mg/kg for E. deightonii, 2154, 3808 and 2154 mg/kg for A. hispidum, P. staudtii and P. lunatus respectively. The extracts at dose levels of 100, 200 and 400 exhibited significant decrease *(P˂ 0.05) in the gastric volume, while the pH of the gastric juice was significant increase *(P˂ 0.05) in the ethanol induced model. The extracts showed minimum inhibition of gastric acid ranging from 16- 90%. The results showed that the methanol extracts of the selected plants possessed antiulcer as well as cytoprotective ability which could be attributed to the presence of the secondary metabolites.
